(1) Field of the Invention
This invention relates to a scanning electron microscope or similar equipment, and more particularly to a scanning electron microscope or similar equipment capable of irradiating a plurality of beams of charged particles onto a specimen and displaying simultaneously the plurality of images of the specimen.
(2) Description of the Prior Art
There have heretofore been known a wide variety of scanning electron microscopes and similar equipment. For example, there is a scanning electron microscope as shown in FIG. 1, in which an electron beam emitted from an electron gun b in a microscope column a is imparted with a scanning movement by a deflection coil d, to which a scanning signal has already been fed from a scanning power supply c, whereby causing the electron beam to irradiate a specimen e while scanning same.
As the electron beams scans the specimen e, secondary electrons or the like are given off from the specimen e and detected by a detector f. Then, a resulting detection signal is amplified by an amplifier g and subsequently fed to a Braun tube (Cathode-ray tube) h, where an image of the specimen is displayed.
In FIG. 1, letters i and j indicate a condenser lens and objective lens respectively.
When observing an IC pattern formed on a silicon wafer by using such a scanning electron microscope, it is necessary in some instances to observe the specimen e at varied angles. In another instance, it may be desirous to observe the specimen e in this manner.
However, with a conventional scanning electron microscope as illustrated in FIG. 1, there are problems such that it takes some time for inclining the specimen e and, in addition, it is rather difficult to find out the same field of vision after the specimen e has been inclined. Such a conventional scanning electron microscope is also accompanied by another problem that it is incapable of obtaining at the same time a plurality of images of the specimen e seen at varied angles.